PI plans to isolate native human isoforms of PGS from (hPGS-1) normal labor tissues and (hPGS-2) infection induced tissues to screen specific tocolytics for use in preterm labor intervention. Also, hPGS-1 and hPGS-2 quantitation in intrauterine tissues and comparison with normal laboring tissues will allow for identification of the most active tissue sites of PGS isoform production.